The present invention generally relates to a protein material and a method for the manufacture of the same and, more particularly, to the preparation of a protein material having an excellent taste-sustaining power, i.e., excellent in giving its taste for a prolonged period of time during chewing or mastication.
Various types of fibrous protein materials and methods for the manufacture thereof have long been well known. Of these known methods, exemplary is a wet spinning method wherein a fibrous protein material is manufactured by preparing an alkaline dope from a refined protein and extruding the dope into a coagulant bath through a spinning nozzle, with or without subsequent elongation and passage in contact with an albumin containing binder to form a tow of protein fibers. In this conventional wet spinning method, addition of a flavoring agent to the material before it is spun is generally difficult because the protein fibers tend to break during the elongation, and, therefore, it is a customary practice to add the flavoring agent in the binder. In addition, the conventional wet spinning method reguires the use of a highly refined protein and is susceptible to change in pH value to such an extent as to result in difficulty in waste water treatment. Thus, the conventional wet spinning method requires a high operating cost.
There is also known a method wherein a protein slurry is forced to flow in heated condition by the use of a heat-exchanger piping or an ejector to texture into the form of fibers. In this known method, a flavoring agent is added to the protein slurry, or the fibrous material after so formed is contacted with the flavoring agent with or without a binder contained therein.
Where the flavoring agent is added to the slurry, not only is the flavoring agent insufficiently taken up in the fibrous material during the coagulation, allowing a portion thereof to elude into the whey, but also the flavor given by the flavoring agent taken up in the fibrous material tends to vanish in a relatively short period of time during chewing or mastication, thereby lacking a sufficient taste-sustaining power. On the other hand, where the flavoring agent is added to the textured fibrous material, it has been found that the fibrous material lacks a sufficient taste-sustaining power and, specifically, when the fibrous material is boiled in water, the flavoring agent tends to elude considerably from the fibrous material, leaving a relatively small amount of the flavoring agent in the fibrous material.